well im a wrestler for my school so im pretty much experienced with weight controll.
first off STOP dinking coke, if you have to drink pop or soda drink only the clear kinds, such as sprite. water will help you lose weight if you drink it because it breaks down all the fatty material you eat into energy to burn. but starvation is usaully the route i take if i need to lose 3 or 4 pounds, its not a healthy way to lose weight but it works.
exercise as much as possible, try to break a good sweat everyday. walk, jog, or run early in the morning for about 30 minutes.

so basicly eating less, trying to keep a healthy diet, and exercising more would do the trick